Ultra-wideband through-the-wall radar antenna

Abstract

The invention discloses an ultra wide band through-the-wall radar antenna which comprises a bow tie antenna. The bow tie antenna comprises antenna arms, wherein each antenna arm comprises a first part and a second part which are arranged along a first direction and are electrically connected; the head parts of the first part and the second part form a bow tie antenna feed part; the tail part of the second part is far away from the first part, the tail part of the second part is provided with a plurality of arc-shaped notches, and the plurality of arc-shaped notches are arranged at intervals along the second direction so as to divide the tail part of the second part into a plurality of bow tie antenna tail end parts; wherein the first direction is perpendicular to the second direction. According to the technical scheme, the tail part of the second part is divided by the arc-shaped gaps to form the plurality of bow-tie antenna tail end parts, so that the input impedance of the bow-tie antenna at the bow-tie antenna tail end parts is changed gently, good impedance matching is easy to realize, reflected current is effectively absorbed, and tail end reflection is effectively reduced; on the premise that miniaturization of the ultra-wideband through-the-wall radar antenna is achieved, the bandwidth of the antenna is improved, and the gain of the antenna is improved.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to an ultra-wideband through-wall radar antenna. Background Art

[0002] With the development of ultra-wideband technology, the application field of ultra-wideband radar is also expanding. Ultra-wideband through-the-wall radar can perform non-invasive detection. It uses electromagnetic wave signals to penetrate non-metallic obstacles and detect targets. This technology has been widely used in military and civilian fields due to its strong penetration ability and high distance resolution. In the military field, ultra-wideband through-the-wall radar can provide non-invasive detection of targets hidden in buildings, thereby improving the reconnaissance and detection capabilities of combatants. In the civilian field, such as disaster search and rescue, ultra-wideband through-the-wall radar can search and rescue people in ruins in earthquakes, landslides and other situations, which is crucial for rapid response and rescue operations. In the above scenarios, ultra-wideband through-the-wall radar technology has been proven to have significant application value and development potential. Generally speaking, ultra-wideband through-the-wall radar needs to have the characteristics of strong penetration, high resolution and good portability to meet the application requirements of different scenarios.

[0003] Radar antenna is a key component of the RF front end of ground penetrating radar, which can realize the effective transmission and reception of electromagnetic waves. In order to realize the characteristics of the above-mentioned ultra-wideband through-wall radar, the antenna needs to meet the requirements of large bandwidth and high gain while maintaining miniaturization.

[0004] At present, there are contradictions between the three indicators of size, bandwidth and gain of ultra-wideband through-wall radar antennas. Common high-gain antennas are large in size and cannot meet the requirements of portability. In order to achieve miniaturization, some ultra-wideband through-wall radar antennas sacrifice high-frequency characteristics, resulting in insufficient bandwidth.

[0005] Therefore, how to achieve ultra-wideband while ensuring a certain gain under the premise of miniaturization of the antenna is a problem to be solved in this technical field. Summary of the invention

[0006] In view of this, the present invention provides an ultra-wideband through-wall radar antenna. By opening an arc-shaped notch at the tail of the ultra-wideband through-wall radar antenna, the antenna bandwidth and the antenna gain can be increased while miniaturizing the ultra-wideband through-wall radar antenna.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] An ultra-wideband through-wall radar antenna, comprising: a bowtie antenna;

[0009] The bow tie antenna comprises: two antenna arms which are symmetrically distributed and electrically connected, each of the antenna arms comprises: a first portion and a second portion which are arranged along a first direction and electrically connected;

[0010] The first part and the head of the second part constitute a feeding part of the bow tie antenna;

[0011] The tail of the second part is far away from the first part, and the tail of the second part has a plurality of arc-shaped notches, and the plurality of arc-shaped notches are arranged at intervals along the second direction to divide the tail of the second part into a plurality of bowtie antenna terminal parts;

[0012] The first direction and the second direction are perpendicular to each other.

[0013] Preferably, the overall cross-section of the feeding portion of the bowtie antenna is semi-elliptical;

[0014] There are two arc-shaped notches, each of which has two symmetrically arranged arc edges, and each of which is adapted to the arc-shaped protruding edge of the end portion of the bow tie antenna; the two arc-shaped notches divide the tail portion of the second part into three end portions of the bow tie antenna, so that the overall cross-section of the bow tie antenna is in the shape of a clover leaf.

[0015] Preferably, each of the antenna arms further comprises: a metal sheet, a slot chip resistor and an end chip resistor;

[0016] The number of the terminal patch resistors is a plurality of terminal portions connected one-to-one with the terminal portions of the plurality of bow tie antennas, so that each terminal portion of the bow tie antenna is connected to the metal sheet through the corresponding terminal patch resistor;

[0017] The first part and the second part are electrically connected via a slot chip resistor.

[0018] Preferably, the metal sheet is provided with a through hole penetrating along its axial direction, the through hole is used to conduct the feeding circulation current, and the through hole is an assembly through hole assembled with a fastener.

[0019] Preferably, the bowtie antenna further comprises: an antenna dielectric substrate;

[0020] The length direction of the antenna dielectric substrate is parallel to the first direction, and the width direction of the antenna dielectric substrate is parallel to the second direction;

[0021] The two antenna arms are arranged on the antenna dielectric substrate along the length direction of the antenna dielectric substrate.

[0022] Preferably, it also includes: a metal wall and a magnetic conductor;

[0023] The bowtie antenna and the magnetic conductor are arranged parallel to each other from top to bottom and at intervals, and the center position of the bowtie antenna and the center position of the magnetic conductor are located on the same straight line;

[0024] The metal walls are two symmetrically arranged vertically, and one of the metal walls, the bowtie antenna, the other metal wall and the head and tail sides of the magnetic conductor are connected in sequence to form a rectangular frame structure.

[0025] Preferably, the number of the bow tie antennas is two, one is an original bow tie antenna, and the other is a parasitic bow tie antenna;

[0026] The original bowtie antenna, the parasitic bowtie antenna and the magnetic conductor are arranged in parallel and spaced apart from top to bottom, and the center position of the original bowtie antenna, the center position of the parasitic bowtie antenna and the center position of the magnetic conductor are located on the same straight line.

[0027] Preferably, the magnetic conductor comprises: a magnetic conductor medium substrate and a plurality of magnetic conductor units;

[0028] A plurality of magnetic conductor units are arranged on the magnetic conductor medium substrate.

[0029] Preferably, it also includes: a lens;

[0030] The lenses are arranged in parallel and at intervals on the original bow tie antenna, and the center position of the lens and the center position of the original bow tie antenna are located on the same straight line.

[0031] Preferably, the lens comprises: a lens medium substrate and a plurality of lens units;

[0032] A plurality of the lens units are arranged on the lens dielectric substrate.

[0033] It can be seen from the above technical solution that the ultra-wideband through-wall radar antenna provided by the present invention has a plurality of bowtie antenna end portions formed by dividing the tail portion of the second portion by an arc-shaped notch, so that the input impedance of the bowtie antenna at the end portion of the bowtie antenna with an arc-shaped edge changes smoothly, and it is easy to achieve good impedance matching, and can effectively absorb reflected current. It can also effectively reduce the end reflection of the ultra-wideband through-wall radar antenna, and on the premise of realizing the miniaturization of the ultra-wideband through-wall radar antenna, the antenna bandwidth is improved and the antenna gain is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 A schematic diagram of the overall structure of an ultra-wideband through-wall radar antenna provided by an embodiment of the present invention;

[0036] Figure 2 A schematic diagram of a top view structure of a lens provided in an embodiment of the present invention;

[0037] Figure 3 A schematic diagram of a top view of the bowtie antenna provided in an embodiment of the present invention;

[0038] Figure 4 A schematic diagram of specific dimensions of a bowtie antenna provided in an embodiment of the present invention;

[0039] Figure 5 A schematic diagram of the structure of a magnetic conductor provided by an embodiment of the present invention;

[0040] Figure 6 Schematic diagram of voltage standing wave ratio (VSWR) results of four structural antennas;

[0041] Figure 7 Schematic diagram of the achievable gain (Realized Gain) results of four structural antennas.

[0042] The meanings of the reference numerals in the figures are as follows:

[0043] 1 is a lens, 11 is a lens medium substrate, and 12 is a lens unit;

[0044] 2 is the original bow tie antenna, 3 is the parasitic bow tie antenna, 21 is the antenna arm, 22 is the antenna dielectric substrate, 23 is the through hole, 24 is the metal sheet, 25 is the gap chip resistor, 26 is the end chip resistor, 27 is the arc notch, 28 is the first part, and 29 is the second part;

[0045] 4 is a metal wall;

[0046] 5 is a magnetic conductor, 51 is a magnetic conductor medium substrate, and 52 is a magnetic conductor unit. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] An ultra-wideband through-wall radar antenna provided by an embodiment of the present invention is Figure 1-Figure 5 As shown, it includes: a bow tie antenna (i.e., a Bow-tie antenna);

[0049] The bow tie antenna comprises: two antenna arms 21 which are symmetrically distributed and electrically connected, each antenna arm 21 comprises: a first portion 28 and a second portion 29 which are arranged along a first direction and electrically connected;

[0050] The first portion 28 and the head of the second portion 29 constitute the feeding portion of the bow tie antenna;

[0051] The tail of the second part 29 is away from the first part 28, and the tail of the second part 29 has a plurality of arc-shaped notches 27, and the plurality of arc-shaped notches 27 are arranged at intervals along the second direction to divide the tail of the second part 29 into a plurality of bow tie antenna terminal parts;

[0052] The first direction and the second direction are perpendicular to each other.

[0053] In the above technical solution, compared with the prior art, the power supply is connected to the connection circuit between the two antenna arms 21 to provide current input for the feeding loop, thereby enabling the ultra-wideband through-the-wall radar antenna to start operating (radiating and receiving electromagnetic waves). Since the tail portion of the second part is divided by the arc-shaped notch 27 to form a plurality of bowtie antenna end portions, the input impedance of the bowtie antenna with an arc-shaped edge at the end portion of the bowtie antenna changes smoothly, which is easy to achieve good impedance matching, can effectively absorb reflected current, and can also effectively reduce the end reflection of the ultra-wideband through-the-wall radar antenna. On the premise of realizing the miniaturization of the ultra-wideband through-the-wall radar antenna, the antenna bandwidth can be improved and the gain of the ultra-wideband through-the-wall radar antenna can be improved.

[0054] Optimize the above technical solutions, such as Figure 3 and Figure 4 As shown, the overall cross-section of the feeding portion of the bowtie antenna is semi-elliptical;

[0055] There are two arc-shaped notches 27, each of which has two symmetrically arranged arc edges, and each arc edge is adapted to the arc-shaped protruding edge of the end portion of the bow tie antenna; the two arc-shaped notches 27 divide the tail portion of the second portion 29 into three bow tie antenna end portions, so that the overall cross-section of the bow tie antenna is in the shape of a clover leaf.

[0056] In the above technical solution, the bow tie antenna is configured as a cloverleaf shape as a whole, which is beneficial to improving antenna gain and miniaturization, and further improving antenna bandwidth and antenna gain.

[0057] To optimize the above technical solution, each antenna arm 21 further includes: a metal sheet 24, a slot chip resistor 25 and an end chip resistor 26;

[0058] The number of the terminal patch resistors 26 is a plurality of terminal patch resistors 26 connected one by one to the terminal portions of the plurality of bow tie antennas, so that each terminal portion of the bow tie antenna is connected to the metal sheet 24 through the corresponding terminal patch resistor 26. The length of the metal sheet 24 is l 24 =11mm, width w 24 =64mm, such as Figure 4 As shown;

[0059] The first portion 28 and the second portion 29 are electrically connected via the slot chip resistor 25 .

[0060] In the above technical solution, the end of the arc-shaped bowtie antenna is loaded with resistance at the end, which can effectively absorb the reflected current, realize the miniaturization of the antenna, further improve the antenna bandwidth, and improve the antenna gain; and the slot chip resistor 25 and the end chip resistor 26 are industrial products, which are not easy to be damaged, which is beneficial to prolong the service life of the ultra-wideband through-wall radar antenna; as a preferred embodiment, the number of slot chip resistors 25 is two symmetrically arranged; in addition, it should be noted that the metal sheet 24 flows to the metal wall 4, which extends the current path and realizes the miniaturization of the antenna; of course, in addition to the function of conducting the circuit, the metal sheet 24 also has the function of protecting the antenna dielectric substrate 22 to prevent it from being damaged.

[0061] Further optimization of the above technical solution, such as Figure 3 and Figure 4 As shown, the distance between the gap chip resistor 25 and the feeding center is l 25 =15mm, the gap width of the gap chip resistor 25 is w 25 =1mm; the front half of each antenna arm 21 (i.e., the bow tie antenna feeding portion) is a semi-ellipse, and its major semi-axis l 212 =26mm, short semi-axis w 212 =22mm. The three tail lobes of the rear half (i.e., the tail of the second part 29) are composed of a quarter ellipse and a semi-ellipse. The major semi-axis of the semi-ellipse of the rear half is l 213 =20mm, the minor axis is w 213 =9mm. The major axis of the second quarter ellipse is l 213 =20mm, the minor axis is w 214 =15mm. The gap length corresponding to the end chip resistor 26 is l 26 =1mm.

[0062] Further optimization of the above technical solution, such as Figure 3 and Figure 4 As shown, the metal sheet 24 is provided with a through hole 23 penetrating along the axial direction thereof, the through hole 23 is used for conducting the feeding circulation current, and the through hole 23 is an assembly through hole assembled with a fastener.

[0063] In the present technical solution, the current sequentially passes through the metal sheet 24 and the through hole 23 to the metal wall 4, thereby extending the current path and realizing the miniaturization of the antenna. Preferably, the bow tie antenna is fixed to other parts by fasteners passing through the through hole 23 (in this case, the fasteners have the function of assembly). Of course, the fasteners also have the function of current transmission. It should be noted that the diameter of the through hole 23 is d 23 =2mm.

[0064] Optimize the above technical solutions, such as Figure 3 As shown, the bow tie antenna further includes: an antenna dielectric substrate 22;

[0065] The length direction of the antenna dielectric substrate 22 is parallel to the first direction, and the width direction of the antenna dielectric substrate 22 is parallel to the second direction;

[0066] The two antenna arms 21 are arranged on the antenna dielectric substrate 22 along the length direction of the antenna dielectric substrate 22; it should be noted that the antenna arms 21 are made of metal;

[0067] In the above technical solution, the antenna dielectric substrate 22 protects and supports the antenna arm 21 disposed thereon. Preferably, the length and width of the antenna dielectric substrate 22 are 120 mm*60 mm, and the material thereof is FR-4 and the thickness is 1.6 mm.

[0068] In this technical solution, if Figure 1 As shown, it also includes: a metal wall 4 and a magnetic conductor 5;

[0069] The bowtie antenna and the magnetic conductor 5 are arranged parallel and spaced from top to bottom, and the center position of the bowtie antenna and the center position of the magnetic conductor 5 are located on the same straight line, and the magnetic conductor 5 is an artificial magnetic conductor;

[0070] There are two metal walls 4 arranged symmetrically vertically, and one metal wall 4, the bowtie antenna, the other metal wall 4 and the magnetic conductor 5 are connected in sequence at the head and tail sides to form a rectangular frame structure; preferably, the connection between one metal wall 4, the bowtie antenna, the other metal wall 4 and the magnetic conductor 5 includes an electrical connection to form a feeding loop.

[0071] One of the above schemes constitutes an ultra-wideband through-wall radar antenna A (including the bowtie antenna, a magnetic conductor and a metal wall, and the overall cross-section of the bowtie antenna is in a clover shape).

[0072] In the above technical solution, the magnetic conductor 5 can achieve a reflection effect with zero phase difference. When placed behind the bowtie antenna, the backward wave of the bowtie antenna can be reflected, and then superimposed in phase with the forward wave of the bowtie antenna, thereby further improving the gain of the ultra-wideband wall-penetrating radar antenna. It should be noted that the rectangular frame structure plays a supporting and protective role. It should be noted that the vertical height of the metal wall 4 is 30 mm.

[0073] Optimize the above technical solutions, such as Figure 1 As shown, there are two bow tie antennas, one is the original bow tie antenna 2, and the other is the parasitic bow tie antenna 3. The structures of the original bow tie antenna 2 and the parasitic bow tie antenna 3 are completely the same;

[0074] The original bow tie antenna 2, the parasitic bow tie antenna 3 and the magnetic conductor 5 are arranged in parallel and spaced apart from top to bottom, and the center position of the original bow tie antenna 2, the center position of the parasitic bow tie antenna 3 and the center position of the magnetic conductor 5 are located on the same straight line; preferably, the original bow tie antenna 2, the metal wall 4 and the magnetic conductor 5 are electrically connected to form a first feeding loop; the parasitic bow tie antenna 3, the metal wall 4 and the magnetic conductor 5 are electrically connected to form a second feeding loop.

[0075] One of the above schemes constitutes an ultra-wideband through-wall radar antenna B (including an original bowtie antenna, a magnetic conductor, a metal wall and a parasitic bowtie antenna, wherein the overall cross-section of the bowtie antenna is in a clover shape).

[0076] In the above technical solution, the parasitic bowtie antenna 3 as a parasitic structure can be mutually coupled with the original bowtie antenna 2 to compensate for the problem of poor capacitive matching at low frequencies of the antenna, and further expand the bandwidth of the low frequencies of the antenna.

[0077] Further optimization of the above technical solution, such as Figure 5 As shown, the magnetic conductor 5 includes: a magnetic conductor medium substrate 51 and a plurality of magnetic conductor units 52;

[0078] Multiple magnetic conductor units 52 are arranged on a magnetic conductor medium substrate 51. The arrangement of multiple magnetic conductor units 52 further improves the antenna gain. It should be noted that the magnetic conductor 5 can achieve a reflection effect with zero phase difference compared to a traditional metal backplane, and makes the structure of the ultra-wideband through-wall radar antenna more compact. It should also be noted that the magnetic conductor 5 is an artificial magnetic conductor.

[0079] In one embodiment, if Figure 5 As shown, the structure is composed of 6*3 magnetic conductor units 52 and a magnetic conductor medium substrate 51. The eighteen magnetic conductor units 52 are arranged in three columns, each column containing six magnetic conductor units 52. The magnetic conductor unit 52 is a square metal sheet with a side length of l 52 =17mm, outer length is l51 =20mm. The magnetic conductor medium substrate 51 is made of Taconic-cer10 plate with a thickness of 1.6mm.

[0080] Further optimization of the above technical solution, such as Figure 1 As shown, it also includes: a lens 1;

[0081] The lens 1 is arranged parallel to and spaced apart from the original bow tie antenna 2 , and the center position of the lens 1 and the center position of the original bow tie antenna 2 are located on the same straight line.

[0082] In the above technical solution, the lens 1 can increase the refractive index when the electromagnetic wave passes through, enhance the convergence effect of the antenna forward wave, and further improve the gain of the antenna; preferably, the material of the lens 1 is a metamaterial.

[0083] One of the above schemes constitutes an ultra-wideband through-wall radar antenna C (including the original bowtie antenna, a magnetic conductor, a metal wall, a parasitic bowtie antenna and a lens, wherein the overall cross-section of the bowtie antenna is in the shape of a clover leaf).

[0084] In one embodiment, if Figure 1 As shown, the interval h1 between the lens 1 and the original bow tie antenna 2 is 20 mm, the interval h2 between the original bow tie antenna 2 and the parasitic bow tie antenna 3 is 10 mm, and the interval h3 between the parasitic bow tie antenna 3 and the magnetic conductor 5 is 30 mm.

[0085] Further optimize the above technical solution, such as Figure 1 and Figure 2 As shown, the lens 1 comprises: a lens dielectric substrate 11 and a plurality of lens units 12;

[0086] A plurality of lens units 12 are arranged on the lens dielectric substrate 11. Such an arrangement can enhance the convergence effect of the antenna forward wave and further improve the gain of the antenna.

[0087] In one embodiment, if Figure 2 As shown, the lens 1 is composed of 4*2 lens units 12 and a lens dielectric substrate 11. The eight lens units 12 are arranged in two adjacent rows, wherein four lens units 12 are in one row and the other four lens units 12 are in another row. It should also be noted that the lens unit 12 is a metal ring, and the lens dielectric substrate 11 is made of FR-4 plate with a thickness of 1.6 mm. In one embodiment, the distance between the lens 1 and the parasitic bowtie antenna 2 is h1=20 mm, and the outer radius of the lens unit 12 is r 121 =8mm inner radius is r 122 =13mm; wherein, the material of the lens dielectric substrate 11 and the lens unit 12 is metamaterial.

[0088] In another embodiment, the length and width of the lens 1, the parasitic bowtie antenna 2, the original bowtie antenna 3 and the magnetic conductor 5 are kept consistent (that is, the projections in the vertical direction, the edges of the four completely overlap); in another embodiment, the spacing between the two antenna arms 21 is l 211 =3mm, such as Figure 4 shown.

[0089] The technical features mentioned above, the technical features to be mentioned below, and the technical features shown separately in the drawings can be combined with each other arbitrarily, as long as the combined technical features are not contradictory. All feasible feature combinations are technical contents clearly recorded in this article. Any of the multiple sub-features contained in the same sentence can be applied independently, and does not have to be applied together with other sub-features.

[0090] The effect of the present invention can be further illustrated by the following simulation results:

[0091] Simulation conditions: The antenna is simulated and parameter optimized by ANSYS HFSS electromagnetic simulation software. The materials of the antenna and substrate are set according to the above parameters, and then the boundary conditions are set, and the sweep frequency range is added to be 300MHz~2GHz. Then four antennas are simulated. The four antennas are traditional antennas (including traditional semi-elliptical bow tie antennas and back cavities), ultra-wideband through-wall radar antenna A, ultra-wideband through-wall radar antenna B, and ultra-wideband through-wall radar antenna C.

[0092] Simulation 1, such as Figure 6 The voltage standing wave ratio (VSWR) results of four types of antenna structures are shown. Among them, the fourth type of ultra-wideband through-wall radar antenna structure shows that the ultra-wideband through-wall radar antenna C has the widest standing wave bandwidth, which can cover 0.22GHz to 1.93GHz. The relative bandwidth is 159%.

[0093] Simulation 2, such as Figure 7 The figure shows the achievable gain results of the four structural antennas. It can be seen that the high-frequency gain of the ultra-wideband through-wall radar antenna C is significantly improved compared with traditional antennas, up to 7.0dB. Compared with the traditional cavity-backed semi-elliptical bowtie antenna, the gain is increased by 4.4dB.

[0094] In summary, the electrical size of the ultra-wideband through-the-wall radar antenna C is 0.43λ0*0.22λ0*0.22λ0, where λ0 is the wavelength corresponding to the antenna center frequency of 1.08 GHz, and the height of the back cavity of the traditional antenna requires a size of 0.25λ0 alone. Therefore, the ultra-wideband through-the-wall radar antenna C is the optimal solution (i.e., including the setting of lens, original bowtie antenna, parasitic bowtie antenna, metal wall and magnetic conductor). After multi-layer metamaterial loading, not only the gain is improved by 4.4 dB, but also a lower profile height and compact structure are maintained, while achieving a relative bandwidth of 159%.

[0095] The key points and protection points of this application are:

[0096] 1. The present invention forms a cloverleaf structure by making an arc-shaped groove at the end of the semi-elliptical bowtie antenna, which can effectively reduce the reflection at the end of the antenna and improve the antenna bandwidth.

[0097] 2. The present invention greatly expands the low-frequency bandwidth of the antenna through parasitic antenna technology, effectively realizing the miniaturization of the antenna.

[0098] 3. The antenna of the present invention prolongs the effective path of the current by loading the magnetic conductor and the metal wall, and can make the backward wave and the forward wave of the antenna superimposed in phase while achieving miniaturization, thereby improving the antenna gain.

[0099] Fourth, the antenna of the present invention is loaded with a lens, and the unit of the lens adopts a simple ring structure, which can effectively improve the gain without any complex topology, and has a low profile and maintains a compact structure.

[0100] 5. The final antenna can cover the frequency band of 0.22GHz to 1.93GHz, achieving a relative bandwidth of 159%. The gain can reach up to 7.0dB, which is 4.4dB higher than the traditional antenna. According to the principle of electromagnetic field, the antenna with the same structure can also work in other frequency bands by scaling down, so the structure that is proportionally enlarged or reduced on the basis of the present invention is also within the protection scope of the present invention.

[0101] Advantages of the present invention:

[0102] 1. The present invention forms a cloverleaf structure by making an arc-shaped groove at the end of the semi-elliptical bow tie antenna, and at the same time uses the metal side wall to extend the current path to reduce the end reflection current, and finally can cover the frequency band of 0.22GHz to 1.93GHz, with a relative bandwidth of 159%.

[0103] 2. The present invention uses parasitic antenna technology, and the structure of the parasitic antenna is the same as the original antenna, and does not require the design of additional shapes, which reduces the design difficulty and can effectively improve the low-frequency standing wave of the antenna to achieve miniaturization of the antenna.

[0104] 3. The antenna of the present invention is loaded with magnetic conductors and lenses, which ensures a low profile while enabling the antenna's backward wave and forward wave to be superimposed in phase, with a gain of up to 7.0 dB. Compared with the traditional cavity-backed semi-elliptical Bow-tie antenna, the gain can be increased by about 4.4 dB.

[0105] 4. The ultra-wideband through-wall radar antenna C is 0.43λ0*0.22λ0*0.22λ0, where λ0 is the wavelength corresponding to the antenna center frequency of 1.08GHz. The height of the back cavity of the traditional antenna requires a size of 0.25λ0 alone. Therefore, after multi-layer metamaterial loading, this patent not only increases the gain by 4.4dB, but also maintains a lower profile height and compact structure, while achieving a relative bandwidth of 159%.

[0106] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0107] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An ultra-wideband through-wall radar antenna, characterized in that: include: Bow tie antenna; The bow tie antenna comprises: two antenna arms (21) that are symmetrically distributed and electrically connected, each of the antenna arms (21) comprising: a first portion (28) and a second portion (29) that are arranged along a first direction and electrically connected; The first part (28) and the head of the second part (29) constitute a bow tie antenna feeding part; The tail of the second part (29) is far away from the first part (28), and the tail of the second part (29) has a plurality of arc-shaped notches (27), and the plurality of arc-shaped notches (27) are arranged at intervals along the second direction to divide the tail of the second part (29) into a plurality of bow tie antenna terminal parts; The first direction and the second direction are perpendicular to each other.

2. The ultra-wideband through-wall radar antenna according to claim 1, characterized in that: The overall cross-section of the bowtie antenna feeding portion is semi-elliptical; The number of the arc-shaped notches (27) is two, each of the arc-shaped notches (27) has two symmetrically arranged arc edges, and each of the arc edges is adapted to the arc-shaped protruding edge of the end portion of the bow tie antenna; the two arc-shaped notches (27) divide the tail portion of the second portion (29) into three end portions of the bow tie antenna, so that the overall cross-section of the bow tie antenna is in the shape of a clover leaf.

3. The ultra-wideband through-wall radar antenna according to claim 1, characterized in that: Each of the antenna arms (21) further comprises: a metal sheet (24), a slot chip resistor (25) and an end chip resistor (26); The number of the terminal patch resistors (26) is a plurality connected one-to-one with the terminal parts of the plurality of bow tie antennas, so that each terminal part of the bow tie antenna is connected to the metal sheet (24) through the corresponding terminal patch resistor (26); The first part (28) and the second part (29) are electrically connected via a slot chip resistor (25).

4. The ultra-wideband through-wall radar antenna according to claim 3, characterized in that: The metal sheet (24) is provided with a through hole (23) penetrating along its axial direction, the through hole (23) is used to conduct a feeding circulating current, and the through hole (23) is an assembly through hole assembled with a fastener.

5. The ultra-wideband through-wall radar antenna according to claim 1, characterized in that: The bow tie antenna further comprises: an antenna dielectric substrate (22); The length direction of the antenna dielectric substrate (22) is parallel to the first direction, and the width direction of the antenna dielectric substrate (22) is parallel to the second direction; The two antenna arms (21) are arranged on the antenna dielectric substrate (22) along the length direction of the antenna dielectric substrate (22).

6. The ultra-wideband through-wall radar antenna according to any one of claims 1 to 5, further comprising: A metal wall (4) and a magnetic conductor (5); The bowtie antenna and the magnetic conductor (5) are arranged parallel to each other from top to bottom and at intervals, and the center position of the bowtie antenna and the center position of the magnetic conductor (5) are located on the same straight line; The metal walls (4) are two symmetrically arranged vertically, and one of the metal walls (4), the bowtie antenna, the other metal wall (4) and the magnetic conductor (5) are connected in sequence at the head and tail sides to form a rectangular frame structure.

7. The ultra-wideband through-wall radar antenna according to claim 6, characterized in that: The number of the bow tie antennas is two, one is an original bow tie antenna (2), and the other is a parasitic bow tie antenna (3); The original bow tie antenna (2), the parasitic bow tie antenna (3) and the magnetic conductor (5) are arranged in parallel and at intervals from top to bottom, and the center position of the original bow tie antenna (2), the center position of the parasitic bow tie antenna (3) and the center position of the magnetic conductor (5) are located on the same straight line.

8. The ultra-wideband through-wall radar antenna according to claim 6, characterized in that: The magnetic conductor (5) comprises: a magnetic conductor medium substrate (51) and a plurality of magnetic conductor units (52); A plurality of magnetic conductor units (52) are arranged on the magnetic conductor medium substrate (51).

9. The ultra-wideband through-wall radar antenna according to claim 7, characterized in that: Also includes: Lens (1); The lenses (1) are arranged in parallel and at intervals on the original bow tie antenna (2), and the center position of the lens (1) and the center position of the original bow tie antenna (2) are located on the same straight line.

10. The ultra-wideband through-wall radar antenna according to claim 9, wherein the lens (1) comprises: A lens dielectric substrate (11) and a plurality of lens units (12); A plurality of lens units (12) are arranged on the lens medium substrate (11).

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